MULTIMODAL POLYETHYLENE THIN FILM

• US 20190330390A1
• Filed: 09/08/2017
• Published: 10/31/2019
• Est. Priority Date: 09/12/2016
• Status: Abandoned Application

• Current Assignee: Thai Polyethylene Co., Ltd. (SIAM Cement Public Company Limited)
• Original Assignee: Thai Polyethylene Co., Ltd. (SIAM Cement Public Company Limited)
• Inventors: MATTAYAN, Arunsri, TRAISILANUN, Saranya, CHEEVASRIRUNGRUANG, Watcharee, KLOMKAMOL, Warachad
• Application Number:
  US16/332,007
• Publication Number:
  US 20190330390A1
• Time in Patent Office: Days
• CPC Class Codes: B01D 19/0005 with one or more auxiliary substances
• CPC Class Codes: B01J 19/245 placed in series
• CPC Class Codes: B01J 2219/0004 Processes in series
• CPC Class Codes: B01J 8/008 Details of the reactor or of the particulate material; Processes to increase or to retard the rate of reaction B01J8/0285, B01J8/067, B01J8/087, B01J8/1836 take precedence
• CPC Class Codes: B01J 8/22 gas being introduced into the liquid
• CPC Class Codes: C08F 10/02 Ethene
• CPC Class Codes: C08F 2/00 Processes of polymerisation
• CPC Class Codes: C08F 2/01 characterised by special features of the polymerisation apparatus used
• CPC Class Codes: C08F 2/12 Polymerisation in non-solvents C08F2/32 takes precedence
• CPC Class Codes: C08F 2/18 Suspension polymerisation
• CPC Class Codes: C08F 2500/01 High molecular weight, e.g. >800,000 Da.
• CPC Class Codes: C08F 2500/05 Bimodal or multimodal molecular weight distribution
• CPC Class Codes: C08F 2500/12 Melt flow index or melt flow ratio
• CPC Class Codes: C08F 2500/16 Syndiotactic
• CPC Class Codes: C08J 2323/06 Polyethene
• CPC Class Codes: C08J 2423/06 Polyethene
• CPC Class Codes: C08J 2423/08 Copolymers of ethene C08J2423/16 takes precedence
• CPC Class Codes: C08J 5/18 Manufacture of films or sheets
• CPC Class Codes: C08L 2203/16 used for films
• CPC Class Codes: C08L 2205/025 containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
• CPC Class Codes: C08L 2205/03 : containing three or more polymers in a blend
• CPC Class Codes: C08L 2207/068 : Ultra high molecular weight polyethylene
• CPC Class Codes: C08L 23/06 : Polyethene
• CPC Class Codes: C08L 23/0815 : Copolymers of ethene with aliphatic 1-olefins

Abstract

The present invention relates to a reactor system for a multimodal polyethylene polymerization process, comprising; (a) a first reactor; (b) a hydrogen removal unit arranged between the first reactor and a second reactor comprising at least one vessel connected with a depressurization equipment, preferably selected from vacuum pump, compressor, blower, ejector or a combination, thereof, the depressurization equipment allowing to adjust an operating pressure to a pressure in a range of 100-200 kPa (abs); (c) the second reactor; and. (d) a third reactor and the use of a film thereof.

Claims

1. A reactor system for a multimodal polyethylene polymerization process, comprising;

(a) a first reactor;

(b) a hydrogen removal unit arranged between the first reactor and a second reactor comprising at least one vessel connected with a depressurization equipment, preferably selected from vacuum pump, compressor, blower, ejector or a combination thereof, the depressurization equipment allowing to adjust an operating pressure to a pressure in a range of 100-200 kPa (abs);

(c) the second reactor; and

(d) a third reactor.

2. The reactor system according to claim 1, wherein the depressurization equipment allows to adjust the operating pressure in the hydrogen removal unit to a pressure in the range of 103-145 kPa (abs), preferably 104-130 kPa (abs), most preferably 105 to 115 kPa (abs).

3. The reactor system according to claim 1, wherein the hydrogen removal unit further contains a stripping column for the separation of hydrogen and a liquid diluent.

4. A process for producing a multimodal polyethylene composition in the reactor system according to claim 1, comprising;

(a) polymerizing ethylene in an inert hydrocarbon medium in the first reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen in an amount of 0.1-95% by mol with respect to the total gas present in the vapor phase in the first reactor to obtain a low molecular weight polyethylene having a weight average molecular weight (Mw) of 20,000 to 90,000 g/mol or medium molecular weight polyethylene having a weight average molecular weight (Mw) of more than 90,000 to 150,000 g/mol wherein the low molecular weight polyethylene, respectively the medium molecular weight polyethylene, has a density at least 0.965 g/cm3, and the low molecular weight polyethylene has MI₂ in the range from 10 to 1,000 g/10 min and the medium molecular weight polyethylene has MI₂ in the range from 0.1 to 10 g/10 min;

(b) removing in the hydrogen removal unit 98.0 to 99.8% by weight of the hydrogen comprised in a slurry mixture obtained from the first reactor at a pressure in the range of 103-145 kPa (abs) and transferring the obtained residual mixture to the second reactor;

(c) polymerizing ethylene and optionally C₄ to C₁₂ α

-olefin comonomer in the second reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and in the presence of hydrogen in an amount obtained in step (b) to obtain a first high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 150,000 to 1,000,000 g/mol or a first ultra high molecular weight polyethylene in the form of a homopolymer or a copolymer having a weight average molecular weight (Mw) of more than 1,000,000 to 5,000,000 g/mol and transferring a resultant mixture to the third reactor; and

(d) polymerizing ethylene, and optionally C₄ to C₁₂ α

-olefin comonomer in the third reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen, wherein the amount of hydrogen in the third reactor is in a range of 0.1-70% by mol, preferably 0.1-60% by mol with respect to the total gas present in the vapor phase in the third reactor or optionally substantial absence of hydrogen to obtain a second high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 150,000 to 1,000,000 g/mol or a second ultra high molecular weight polyethylene in the form of a homopolymer or copolymer having a weight average molecular weight (Mw) of more than 1,000,000 to 5,000,000 g/mol.

5. The process according to claim 4, wherein the removing is removing of 98.0-99.8% by weight of the hydrogen, more preferable 98.0-99.5% by weight, and most preferred 98.0 to 99.1% by weight.

6. The process according to claim 4, wherein the operation pressure in the hydrogen removal unit is in the range of 103-145 kPa(abs), more preferably 104-130 kPa (abs), and most preferred 105 to 115 kPa (abs).

7. A multimodal polyethylene composition obtainable by a process according to claim 4, comprising;

(A) 30 to 65 parts by weight, preferably 40 to 65 parts by weight, preferably 43 to 52 parts by weight, most preferred 44 to 50 parts by weight, of the low molecular weight polyethylene, the low molecular weight polyethylene having a weight average molecular weight (Mw) of 20,000 to 90,000 g/mol and having a MI₂ from 500 to 1,000 g/10 min according to ASTM D 1238;

(B) 8 to 30 party by weight, 8 to 20 parts by weight, preferably 10 to 18 parts by weight, most preferred 10 to 15 parts by weight, of the first high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 150,000 to 1,000,000 g/mol or the first ultra high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 1,000,000 to 5,000,000 g/mol; and

(C) 30 to 50 parts by weight, preferably 37 to 47 parts by weight, most preferred 39 to 45 parts by weight, of the second high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 150,000 to 1,000,000 g/mol or the second ultra high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 1,000,000 to 5,000,000 g/mole, wherein

the density of the first high molecular weight polyethylene or the first ultra high molecular weight polyethylene and the second high molecular weight polyethylene or the second ultra high molecular weight polyethylene are in the range from 0.920 to 0.950 g/cm³, and

wherein the molecular weight distribution of the multimodal polyethylene composition is from 13 to 60, preferably 20 to 28, preferably from 24 to 28, measured by gel permeation chromatography.

8. The multimodal polyethylene composition according to claim 7, wherein the MI₂ is from 600 to 800 g/10 min.

9. The multimodal polyethylene composition according to claim 7, wherein the molecular weight distribution is from 23 to 28, preferably from 24 to 26, and more preferably from 25 to 26 measured by gel permeation chromatography.

10. The multimodal polyethylene composition according to claim 7, wherein the multimodal polyethylene composition has a weight average molecular weight from 80,000 to 1,300,000 g/mol, preferably 150,000 to 400,000 g/mol, preferably from 200,000 to 350,000 g/mol, measured by Gel Permeation Chromatography.

11. The multimodal polyethylene composition according to claim 7, wherein the multimodal polyethylene composition has a number average molecular weight from 5,000 to 30,000 g/mol, 5,000 to 15,000 g/mol, preferably 7,000 to 12,000 g/mol, measured by Gel Permeation Chromatography.

12. The multimodal polyethylene composition according to claim 7, wherein the multimodal polyethylene composition has a Z average molecular weight from 900,000 to 6,000,000 g/mol, 1,000,000 to 3,000,000 g/mol, preferably from 1,000,000 to 2,500,000 g/mol, measured by Gel Permeation Chromatography.

13. The polyethylene composition according to claim 7 wherein the multimodal polyethylene composition has a density from 0.950 to 0.962 g/cm³, preferably from 0.953 to 0.959 g/cm³, according to ASTM D 1505 and/or a melt flow index MI₅ from 0.01 to 50 g/10 min, and/or MI₂ from 0.03 to 0.15 g/10 min preferably from 0.03 to 0.10 g/10 min.

14. The polyethylene composition according to claim 13, wherein the MI₅ is from 0.01 to 1 g/10 min.

15. Film comprising the multimodal polyethylene composition according to claim 7, wherein the film has a thickness from 4 to 40 μ

m, preferably from 4 to 30 μ

m, and most preferably 4 to 20 μ

m.